(1) Field of the Invention
The present invention relates to simulating the texture of a sonar image. More particularly, the present invention relates to creating realistic sonar images in which three-dimensional targets can be embedded.
(2) Description of the Prior Art
In current warfare scenarios, operations in shallow water environments are becoming increasingly critical. Accordingly, the use of and interpretation of sonar images for detecting objects or targets on the ocean bottom have become increasingly important.
A sonar image typically is comprised of a matrix of points or picture elements (pixels) displayed on either a cathode ray tube or paper. The points or pixels have a grayness level ranging from 0 to 255 on a grayness scale. Objects normally appear on sonar images as a highlight-shadow combination, particularly when the sonar images are generated by a moving vehicle. A sonar scan for short distances typically comprises a massive amount of data which must be reviewed in short time periods.
While computer interpretations of sonar images have been developed, the majority of interpretations are accomplished by human analysts looking at the sonar scans. As an analyst reviews the scans, the analyst marks areas where specific objects or features are inferred to be present on the ocean bottom. Because of the massive amounts of data that must be reviewed in short time periods, proper training of human analysts is necessary to avoid frequent errors or omissions in both detection and classification.
One aspect of this training is target recognition. Generally, the training consists of presenting to an analyst sonar images in which targets have been embedded. The analyst gradually learns to discern the targets from the background. In order for the training to be effective, the sonar images presented to an analyst ideally would represent real world scenarios.
The current method of embedding targets in realistic sonar images involves cutting and pasting snippets of targets into an actual-image. However, this method creates artifacts and does not preserve the phase of the image. Accordingly, the images that analysts currently are trained on do not represent real world scenarios and the accuracy with which an analyst can identify real world targets may suffer. What are needed are systems and methods of embedding three-dimensional targets in realistic sonar images.